I. Field of the Invention
The present invention generally relates to methods and systems for providing network testing. More particularly, the present invention relates to providing end-to-end testing of An IP-enabled network.
II. Background Information
Service providers wish to deploy internet protocol (IP) vertical services on a network. Vertical services may include, but are not limited to a Voice over IP, and IPTV, for example. In order to deploy IP vertical services, service providers need to effectively provision and troubleshoot network elements included in the network. For example, such a network may employ open system interconnection (OSI) standard for communications including upper layers and lower layers as illustrated in FIG. 4. Layers 7 through 4 comprise the upper layers and layers 3 through 1 comprise the lower layers.
OSI transport services include layers 1 through 4, and are collectively responsible for delivering a complete message or file from sending to receiving station without error. Layer 7 is the application layer. This top layer defines the language and syntax that programs use to communicate with other programs. The application layer represents the purpose of communicating. For example, a program in a client workstation uses commands to request data from a program in the server. Common functions at this layer are opening, closing, reading, and writing files, transferring files and e-mail messages, executing remote jobs, and obtaining directory information about network resources.
Layer 6 is the presentation layer. When data are transmitted between different types of computer systems, the presentation layer negotiates and manages the way data are represented and encoded. For example, it provides a common denominator between ASCII and EBCDIC machines as well as between different floating point and binary formats. This layer is also used for encryption and decryption.
Layer 5 is the session layer and provides coordination of the communications in an orderly manner. It determines one-way or two-way communications and manages the dialog between both parties, for example, making sure that the previous request has been fulfilled before the next one is sent. It also marks significant parts of the transmitted data with checkpoints to allow for fast recovery in the event of a connection failure. In practice, this layer is often not used or services within this layer are sometimes incorporated into the transport layer.
Layer 4 is the transport layer. This layer is responsible for overall end-to-end validity and integrity of the transmission. The lower layers may drop packets, but the transport layer performs a sequence check on the data and ensures that if, for example, a 12 MB file is sent, the full 12 MB is received.
Layers 3 through 1 are the lower layers and are responsible for moving packets from the sending station to the receiving station. Layer 3 is the network layer. The network layer establishes the route between the sender and receiver across switching points, which are typically routers. The most ubiquitous example of this layer is the IP protocol in TCP/IP. IPX, SNA, and AppleTalk are other examples of routable protocols, which means that they include a network address and a station address in their addressing system. This layer is also the switching function of the dial-up telephone system. If all stations are contained within a single network segment, then the routing capability in this layer is not required.
Layer 2 is the data link layer. The data link layer is responsible for node to node validity and integrity of the transmission. The transmitted bits are divided into frames, for example, an Ethernet, Token Ring, or FDDI frame in local area networks (LANs). Frame relay and ATM are also at Layer 2. Layers 1 and 2 are required for every type of communications.
Layer 1 is the physical layer. The physical layer is responsible for passing bits onto and receiving them from the connecting medium. This layer has no understanding of the meaning of the bits, but deals with the electrical and mechanical characteristics of the signals and signaling methods. For example, it comprises the RTS and CTS signals in an RS-232 environment, as well as TDM and FDM techniques for multiplexing data on a line. SONET also provides layer 1 capability.
In the context of the OSI model as described above, conventional systems include some testing capabilities at the layer 1 and layer 2 levels; however, there is no large-scale end-to-end network view. For example, conventional testing consists primarily of legacy narrowband troubleshooting tools, vendor specific diagnostics, and home grown testing solutions. In applying the conventional systems, service providers have learned to interpret and make best guess estimates with the conventional testing solutions. For example, a customer may call a customer service representative with the service provider and may say “I can't connect”, “I can't reach this web address”, “there's something the matter with my e-mail”, or “there's something wrong with my phone which rides over my IP connection.” Without an end-to-end test tool, the service provider may have difficulty isolating the problem. This may lead to not resolving the customer's problem on the first call or having hand-offs between different departments. This may further lead to customer dissatisfaction because the service provider may not be able to resolve the customer's problem on the first call because the service provider may not be able to accurately pinpoint the problem.
Furthermore, conventional systems increase the service provider's operating cost. For example, the service provider may send out equipment because they think the modem is bad, but in the end, the customer's equipment is defective. Or the service provider may dispatch a truck and technician, but then it turns out it is the wrong technician because the problem is in the customer's computer.
In order to be able to deploy IP vertical services, it is desired to be able to effectively provision and troubleshoot network elements that make up the end-to-end IP network using an end-to-end test tool. Looking forward with the expansion of broadband and complex broadband vertical services, service providers are faced with the reality that today's narrowband tools are inadequate to resolve tomorrow's troubles. For example, layer 1 and layer 2 testing will no longer suffice in resolving the customers' issues. True end-to-end broadband testing may be obtained and utilized to accurately troubleshoot not only basic broadband service, but all the planned services offered on top of broadband.